Why does adiabatic compression increase enthalpy?

Hello! The work done by compressed gas is basically heated, and the enthalpy will inevitably increase.

Adiabatic compression means that there is no heat energy exchange between the system and the outside world, but it does not mean that the heat energy of the system will not increase, the work done during compression will increase the internal energy of the gas, and the adiabatic only means that the increased heat energy will not be dissipated.

For example, the pump of a bicycle will become hot when it is compressed quickly, and the process is very fast, and it is approximated that the heat energy is not dissipated (that is, the heat is insulated by fast, and the heat does not have time to go out).

If it helps you, hope.

Problem: Here q=δu-w=u2-u1+(p2v2-p1v1) is not always true.

Target. The condition for it is w=p2v2-p1v1, and the condition for this equation to be true is that p1 and p2 remain the same throughout the process. This is a special thermodynamics.

process, add Joule Thomson.

process, which has its own characteristics, that is, "the temperature rises and falls through the change of pressure in the process of adiabatic enthalpy." “

However, in the general process, the condition that "P1 and P2 remain unchanged respectively" is even more valid. This is actually quite simple, through the basic relations of thermodynamics.

dh=tds+vdp

It is easy to obtain the partial derivative of enthalpy h for pressure p with constant entropy.

Equal to volume v. That is, the slope of your enthalpy diagram is ideally equal to the volume v, which must be positive. The actual working fluid is not so ideal, and there will be deviations, but it is certainly positive.

Summary. H=ΔU+PDV=-P-Outside DV+PDV, because of constant pressure, P-Outside=P, so ΔH=0

Constant pressure, adiabatic enthalpy change formula.

H=ΔU+PDV=-P-Outside DV+PDV, because of constant pressure, P-Outside=P, so ΔH=0

From the first law of thermodynamics: u = q + w If at constant pressure, the thermal effect is denoted as: qp if there is only the volume work:

U = qp - p vqp = u + p v = h (because h = u + pv) So, at constant pressure, the thermal effect is equal to the enthalpy change. Because the enthalpy change is equal to the addition of the product of the thermodynamic energy and the volume of pressure. Whereas, the value of heat is equal to the addition of thermodynamic energy and volumetric work.

Numerically equal. Don't you understand why the enthalpy change under constant capacity is equal to the heat and the void of the sakura is not the same. Because the enthalpy change PV represents the product of pressure and volume, and does not represent the volume of work ridge carrying, the meaning is different.

Because I'm going to count T.

Why does this enthalpy change become mcp,m(t2-t1).

In general, enthalpy change is considered in physical chemistry, and the formula is used: h(t1)—h(t2)= cp(t1-t2).

Summary. Dear, I'm glad to answer for you: Does the enthalpy of the compressor increase when the large displacement compressor mechanism is hot?

According to the principle of thermodynamics, when the enthalpy of a substance increases, its internal energy also increases. Large-displacement compressors generally refer to compressors with large exhaust capacity, which can quickly compress air and other gases into high-temperature and high-pressure gases. In this process, if the enthalpy value is changed by using a compressor closed vessel, the enthalpy will increase as the temperature and pressure increase.

Enthalpy is an important physical quantity that describes the state of a gas, and it is closely related to factors such as temperature, pressure, and composition of the gas. When the compressor is operating, the increase in enthalpy may lead to problems such as damage to the parts or increased temperature due to factors such as materials and manufacturing processes. Therefore, in practical engineering applications, many factors need to be considered comprehensively in order to better ensure the safety and reliability of equipment.

Overall, an increase in enthalpy value is expected when a large displacement compressor compresses a gas while it is hot. However, for specific application scenarios, detailed analyses and calculations are required for different parameter settings and technical requirements.

Dear, I'm glad to answer your question: Does the enthalpy of the compressor increase when the compressor is heated by using a large displacement compression mechanism: it will increase, according to the principle of thermodynamics, when the enthalpy of a substance increases, its internal energy also increases.

Large-displacement compressors generally refer to compressors with large exhaust capacity, which can quickly compress air and other gases into high-temperature and high-pressure gases. In this process, if the enthalpy value is changed by using a compressor closed vessel, the enthalpy will increase as the temperature and pressure increase. The enthalpy value is an important nanocoarse physical quantity to describe the state of the gas, which is closely related to the temperature, pressure and composition of the gas.

When the compressor is operating, the increase in enthalpy may lead to problems such as damage to the parts or increased temperature due to factors such as materials and manufacturing processes. Therefore, in practical engineering applications, many factors need to be considered comprehensively in order to better ensure the safety and reliability of equipment. Overall, an increase in enthalpy value is expected when a large displacement compressor compresses a gas while it is hot.

However, for specific application scenarios, detailed analyses and calculations are required for different parameter settings and technical requirements.

Dear, please refer to Oh, when the large displacement compressor is heated, the enthalpy of the compressor will increase. The compressor compresses the gas at low pressure and low temperature into the gas with high pressure and high temperature, and due to the large volume of the large displacement compressor, it needs more power than the small displacement compressor when compressing. When using a large displacement compressor for heating, more energy is required to make it work, which will increase the enthalpy of the axle compressor and flush out.

Hello, when using a large displacement compressor for thermal compression, the enthalpy increases. Enthalpy is a physical quantity in thermodynamics that represents the sum of the internal energy of the system and the work done to the outside world. In compressors, the change in enthalpy refers to the working state of the compressor.

When thermal compression is performed with a large displacement compressor, the compressor compresses the gas, reducing its volume and increasing the temperature. As a result, the enthalpy value also increases. In addition, another feature of large displacement compressors is that more gas can be compressed per unit time, which also leads to an increase in enthalpy.

Extraneous expansion: Large displacement compressors have a wide range of applications in industrial production, such as air compressors, refrigeration compressors, etc. When using a large displacement compressor, attention needs to be paid to its power and efficiency to ensure its normal operation and energy saving.

Enthalpy changes are the amount of change in the enthalpy of an object. [1] Enthalpy is a combination of internal energy and flow work

The enthalpy change is the enthalpy difference between the product and the reactant. As a state function that describes the state of a system, enthalpy change has no definite physical significance.

h (enthalpy change) is the increment of the enthalpy of a process in which the system takes place. ΔH = ΔU + δ (PV) Under constant pressure conditions, ΔH (enthalpy change) is equal to the constant pressure heat of reaction. Enthalpy change is one of the important factors restricting whether a chemical reaction can occur or not, and the other is entropy change.

Entropy increases and decreases, and the reaction is spontaneous; The enthalpy of entropy reduction increases, and the reaction is reversed and spontaneous; Entropy increases, enthalpy increases, and high temperature reactions are spontaneous; Entropy decreases enthalpy, and low-temperature reactions are spontaneous. The enthalpy change of the adiabatic isobaric process is equal to the isobaric thermal effect, and the isobaric thermal effect cannot be calculated by the isobaric heat capacity. Adiabatic q=o isobaric δp=0, the definition of thermodynamic energy δu=q+w=w, however, the definition δh=δu+δpv, δu=w=-p dv and δp=0, therefore, δh=-pdv+δpv=0, so the enthalpy becomes zero in the adiabatic isobaric process of an ideal gas, this can be demonstrated.

It should be noted that p at this time is the external pressure, and δh=nδ, and the isopressure in is the constant pressure of the system (equal to the external pressure), and the two are different. For an adiabatic isobaric process, either the system pressure is not equal to the external pressure (in this case, it is an irreversible process), the system pressure is not constant, and δH=Nδ is not true; Either the system pressure is equal to the external pressure, but there is non-volumetric work, as in the phase transformation process, and δh=nδ is also not true. Enthalpy is a function of state, that is, the value of enthalpy is determined when the state of the system is fixed.

The definition of enthalpy (enthalpy has no actual physical meaning, but it has operational significance. Here's what it looks like: H = U + PV [enthalpy = flow internal energy + work of propulsion].

where u represents thermodynamic energy, also known as internal energy, that is, all the energy inside the system; p is the pressure of the system, and v is the volume of the system.

The enthalpy change is inseparable from the thermal motion of the molecule. The thermal motion of molecules, known as thermal motion, means that objects are composed of molecules, atoms and ions, water is composed of molecules, iron is composed of atoms, salt is composed of ions, and the molecules of all substances are in constant motion, and it is irregular motion. The thermal motion of the molecule is related to the temperature of the object (thermal motion will also be done in the case of '0' degrees, and the internal energy is based on thermal motion), the higher the temperature of the object, the faster the movement of its molecules.

Brownian Movement Brownian Motion The phenomenon of suspended particles constantly making irregular motion is called Brownian motion, for example, this movement can be seen when you observe Garcinia cambogia and pollen particles suspended in water under a microscope, and the higher the temperature, the more intense the movement. It was 1827 by the botanist RBrown was the first to find out.

The particles that make Brownian motion are very small, about 1 10 nanometers in diameter, and under the collision of surrounding liquid or gas molecules, a fluctuating net force is generated, resulting in the Brownian motion of the particles. If the Brownian particles have little chance of colliding with each other and can be regarded as ideal gases of huge molecular composition, then the distribution of their number densities by height after thermal equilibrium in the gravitational field should follow the Boltzmann distribution. Perran's experiments confirmed this, and he was able to determine the Avogadro constant and a series of particle-related data with considerable precision.

You should first understand what the first mechanics of heat is. It is the internal energy that characterizes the energy of a thermodynamic system. Through work and heat transfer, the system exchanges energy with the outside world, causing some changes in internal energy. According to the universal law of conservation of energy.

After the system reaches the final state from the initial state through an arbitrary process, the increment of the internal energy should be equal to the difference between the heat q transferred by the outside world to the system and the work done by the system to the outside world a, i.e., or This is the first law of thermodynamics.

expression. If, in addition to work and heat transfer, there is also energy z brought in by matter entering the system from the outside world, then it should be . Of course, the above, w, q, and z can all be positive or negative (so that the increase in system energy is positive and the decrease is negative). For infinitesimal ones.

process, the differential expression of the first law of thermodynamics is . Since u is a state function, it is a full differentiation.

q and w are process quantities, and only indicate that the smallest quantities are not fully differential, and the difference is indicated by symbols. In addition, because δu or du only involves the initial and final states, only the initial and final states of the system are required to be equilibrium, regardless of whether the intermediate state is equilibrium or not. For quasi-static processes, there is .

Another formulation of the first law of thermodynamics is that the first type of perpetual motion machine is impossible. This is a machine that many people fantasize about building that can do work continuously without any fuel or power, and a machine that can create something out of nothing and provide energy continuously.

Obviously, the first type of perpetual motion machine violates the law of conservation of energy. <>

1.Wrong. Enthalpy is a function of state, whereas heat is a family of path functions.

2 false. The condition of δh qp is isobaric and no other work is done. If the electrolysis process is not established.

3 False. The enthalpy is a function of the state, and the enthalpy of the state must have a definite value. Whereas, heat is a function of pathways.

Only δh (instead of H) is equal to the heat of the process reed socks under the conditions of isobaric and no other work.

Adiabatic chemical reaction in a closed container cannot exchange heat with the outside world, and the volume remains the same. There may be two reasons for the rapid and substantial decrease in pressure, one is that after the reaction, the number of molecules decreases, which is a chemical reaction; Secondly, the reaction is to absorb heat because the temperature drops, causing the pressure to drop.

The subsequent increase in pressure may be the opposite process, with an increase in temperature, or an increase in the number of molecules.

The pressure drops to only the initial 1 3, if it is a reaction at room temperature, p, t is proportional, which is equivalent to t drop by 2 3, t at room temperature, about 300k, down 200k, such a reaction has not yet been found. It can only be that the number of molecules has decreased, to the original 1 3.

Later to the rise, it may be an increase in temperature.

This diagram is problematic. The reaction process and the release of the heat of reaction are carried out at the same time, and it will not be this kind of reaction first, followed by exothermy.

Unless two successive reactions occur.

If it is an increase in temperature, an increase of 3 times in absolute temperature, about 200 °, is possible, such as combustion. An increase in the number of molecules may also increase the pressure.